Microsoft Windows operating systems include a power function called hibernate that saves the desktop state and random access memory (RAM) contents before closing down. Upon the next boot, the hibernate feature restores the desktop as it was at the end of the prior session. This differs from Shut Down, which dumps RAM contents and closes all programs and files. Upon booting after a standard shut down, the desktop is pristine. If one wants to continue working on a previous project, programs and associated files must be reopened manually.
Although hibernate comes in handy on desktops, it was prompted by the needs of laptop users. Designed to ensure work would not be lost as a result of battery failure in mobile environments, hibernate monitors the state of the battery. Prior to battery depletion all programs and files are automatically saved and the system is powered down. When the machine boots next, the desktop is automatically restored with all programs open where they were left, all work-in-progress intact.
While safety from battery failure is a key advantage of the hibernate setting, it is also useful in many other situations. For example, using hibernate instead of Shut Down on a laptop will conserve battery power if the user will be starting up where he or she left off. Unnecessarily closing programs and files, only to reopen them at the next boot, wastes valuable battery power.
Hibernate can also be a time-saver when a user is interrupted, whether on a laptop or desktop, at home or at the office. For instance, imagine yourself in the middle of a research project with several open browser windows, a document in progress, and a reference spreadsheet. Suddenly you’re called to an impromptu meeting, or it’s time to pick up the kids from school. When using hibernate all open programs and documents (plus RAM contents) are saved with a single click. The next time you turn on the computer, everything effortlessly reassembles itself.
Alternately, you might be called away from the computer assuming you’ll just be a minute or two. One thing can lead to another, and it can be hours before you get back -- if you get back at all. The hibernate feature has an optional setting that will direct it to engage only after a period of idle-time set by the user. For example, a laptop might be set to 15 minutes of idle time before hibernation kicks in. A desktop might be configured for a somewhat longer period of time. If you’re called away, no problem. The computer will go into hibernation for you, saving your work in progress and powering down.
Another power function of the Windows operating system is the Stand By mode. In this mode hardware devices are taken to a low-power state to conserve electricity or battery power, but a small amount of power is still supplied to the system and RAM. To enter Stand By, one can press the Sleep key on a Microsoft-compatible keyboard, or choose “Stand By” from the Windows Shut Down menu. To bring the system out of Stand By, one can press the Wake key, or use the mouse. These options are configurable in the motherboard’s Basic Input-Output System (BIOS) settings.
Hibernate and Stand By options are available from the Control Panel in Windows under Power Options. They can also be accessed in Windows XP by right-clicking on a blank part of the desktop, choosing Properties, clicking the Screen Saver tab, then clicking the Power button.